From 9da2dd90e2e8db8cfb922eb0c064876c146070dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Thu, 16 May 2019 17:06:18 +0200
Subject: [PATCH] gnu: js-mathjax: Avoid "Too many open files" error while
 building.

* gnu/packages/javascript.scm (js-mathjax)[arguments]: Add call to
'close-pipe'.  Previously builds would sometimes fail with EMFILE (this
was non-deterministic as it depends on GC activity.)
---
 gnu/packages/javascript.scm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/javascript.scm b/gnu/packages/javascript.scm
index 8731a44927..e7dcd7962d 100644
--- a/gnu/packages/javascript.scm
+++ b/gnu/packages/javascript.scm
@@ -117,7 +117,11 @@
                   (let ((minified (open-pipe* OPEN_READ "uglify-js" file)))
                     (call-with-output-file installed
                       (lambda (port)
-                        (dump-port minified port)))))
+                        (dump-port minified port)))
+
+                    (let ((exit (close-pipe minified)))
+                      (unless (zero? exit)
+                        (error "dear, uglify-js failed" exit)))))
                  (else
                   (install-file file (dirname installed))))))
             (find-files "."))